The present invention relates generally to a fluid motor construction, and more particularly to an improvement in a fluid motor construction which incorporates a safety arrangement.
It is already known from the prior art to provide fluid motors, including dual-motor constructions -- especially of the radial-piston variety--wherein two fluid motors may be coupled with a common shaft with both motors either be connected in series in a common stream of pressure fluid, or being connected in parallel in a common stream or in parallel in two separate streams of pressure fluids. A fluid motor construction of the dual-motor variety, wherein the motors are arranged in axial parallelism, is already known from my prior U.S. Pat. No. 3,253,806. It is also shown in this patent that the two motors can be driven in mutually opposite directions.
The prior-art constructions of this type are quite satisfactory for many, if not most, applications. However, there are certain instances in which the prior-art constructions do not provide an adequate degree of safety, since they are not proof against failure and since there are applications -- for instance in the aircraft industry--where such failure can result in loss of life and property.
To take just one example, if in a helicopter the rotors are driven by two coupled fluid motors, and if one of the fluid motors becomes defective for whatever reason, the remaining fluid motor cannot turn the drive shaft for the rotors and at the same time overcome the resistance of the defective motor, with the result that the craft will inevitably crash.